Totally stumped on Claws/Inv

Hehe

You're not going to be able to run a seamless FU>Focus>Slash attack chain even if you were running a Claws/SR (with the commensurate 30% +rech that it gets that no one else does). It simply takes too much +rech (313% +rech in FU). You can get excellent dps (and double stack FU on all attacks) with FU>Focus>Slash>Swipe however.

However, if you're willing to go for maximum damage rather than a seamless attack chain, you can go with FU>Focus>Slash>Wait. As long as that wait is .528 seconds or less (re: FU recharges in 3.432 seconds), you'll be getting better DPS than you would with FU>Focus>Slash>Swipe. This requires 250% +rech in FU (hard but not impossible), 100% +rech in Focus, and 64% +rech in Slash.

Here's a more offensively built variant on my Claws/Invuln build that does most of what you're asking about. It does the FU>Focus>Slash>Wait(.528 sec) attack string, is endurance sustainable, gets 67.5% +res (s/l), and manages 40.9 +def (s/l), 38.7 +def (e/n), and 37.8% +def (f/c) with saturated Invinc.

Hero Plan by Mids' Hero Designer 1.401
http://www.cohplanner.com/

Click this DataLink to open the build!

Level 50 Magic Scrapper
Primary Power Set: Claws
Secondary Power Set: Invulnerability
Power Pool: Fitness
Power Pool: Leaping
Power Pool: Speed
Power Pool: Fighting
Ancillary Pool: Body Mastery

Hero Profile:
Level 1: Swipe -- KntkC'bat-Acc/Dmg(A), KntkC'bat-Dmg/Rchg(31), KntkC'bat-Dmg/EndRdx/Rchg(31), KntkC'bat-Dmg/EndRdx(42)
Level 1: Resist Physical Damage -- S'fstPrt-ResDam/Def+(A), RctvArm-ResDam(13), RctvArm-ResDam/EndRdx/Rchg(15), RctvArm-ResDam/EndRdx(37), RctvArm-ResDam/Rchg(39)
Level 2: Slash -- C'ngImp-Acc/Dmg(A), C'ngImp-Dmg/EndRdx(3), C'ngImp-Dmg/Rchg(3), C'ngImp-Acc/Dmg/Rchg(40), C'ngImp-Dmg/EndRdx/Rchg(42), Achilles-ResDeb%(42)
Level 4: Temp Invulnerability -- ImpArm-ResDam(A), ImpArm-ResDam/EndRdx(5), ImpArm-EndRdx/Rchg(5), ImpArm-ResDam/EndRdx/Rchg(40)
Level 6: Dull Pain -- Dct'dW-EndRdx/Rchg(A), Dct'dW-Heal/Rchg(7), Dct'dW-Heal/EndRdx/Rchg(7), Dct'dW-Rchg(15), Dct'dW-Heal(39)
Level 8: Follow Up -- Hectmb-Dmg/Rchg(A), Hectmb-Acc/Dmg/Rchg(9), Hectmb-Acc/Rchg(9), Hectmb-Dmg/EndRdx(11), Hectmb-Dam%(11), RechRdx-I(46)
Level 10: Hurdle -- Jump-I(A)
Level 12: Combat Jumping -- LkGmblr-Rchg+(A), LkGmblr-Def(13)
Level 14: Super Jump -- Zephyr-Travel(A), Zephyr-Travel/EndRdx(43)
Level 16: Unyielding -- ImpArm-ResDam(A), ImpArm-ResDam/EndRdx(17), ImpArm-EndRdx/Rchg(17), ImpArm-ResDam/EndRdx/Rchg(39)
Level 18: Health -- Numna-Regen/Rcvry+(A), Numna-Heal(19), Mrcl-Rcvry+(19), Mrcl-Heal(37)
Level 20: Stamina -- P'Shift-End%(A), P'Shift-EndMod(21), EndMod-I(21)
Level 22: Focus -- Apoc-Dmg/Rchg(A), Apoc-Acc/Dmg/Rchg(23), Apoc-Acc/Rchg(23), Apoc-Dmg/EndRdx(34), Apoc-Dam%(36)
Level 24: Hasten -- RechRdx-I(A), RechRdx-I(25), RechRdx-I(25)
Level 26: Spin -- Armgdn-Dmg/Rchg(A), Armgdn-Acc/Dmg/Rchg(27), Armgdn-Acc/Rchg(27), Armgdn-Dmg/EndRdx(34), Armgdn-Dam%(43)
Level 28: Invincibility -- LkGmblr-Rchg+(A), LkGmblr-Def(29), LkGmblr-Def/EndRdx(29)
Level 30: Resist Elements -- RctvArm-ResDam(A), RctvArm-ResDam/EndRdx/Rchg(31), RctvArm-ResDam/EndRdx(40), RctvArm-ResDam/Rchg(48)
Level 32: Shockwave -- Ragnrk-Dmg(A), Ragnrk-Dmg/Rchg(33), Ragnrk-Acc/Dmg/Rchg(33), Ragnrk-Acc/Rchg(33), Ragnrk-Dmg/EndRdx(34)
Level 35: Tough Hide -- GftotA-Def(A), GftotA-Def/EndRdx(36), GftotA-Def/Rchg(36), GftotA-Run+(37)
Level 38: Resist Energies -- Aegis-ResDam(A), Aegis-ResDam/EndRdx(46), Aegis-ResDam/Rchg(46)
Level 41: Boxing -- Amaze-Stun(A), Amaze-Stun/Rchg(43), Amaze-Acc/Stun/Rchg(50), Amaze-Acc/Rchg(50), Amaze-EndRdx/Stun(50)
Level 44: Tough -- ImpArm-ResDam(A), ImpArm-ResDam/EndRdx(45), ImpArm-EndRdx/Rchg(45), ImpArm-ResDam/EndRdx/Rchg(45)
Level 47: Weave -- LkGmblr-Rchg+(A), LkGmblr-Def(48), LkGmblr-Def/EndRdx(48)
Level 49: Conserve Power -- RechRdx-I(A)
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Level 1: Brawl -- Empty(A)
Level 1: Sprint -- Empty(A)
Level 2: Rest -- Empty(A)
Level 1: Critical Hit